Cancer, heart disease, type-2 diabetes, infections and obesity have all been linked to reduced sleep.

The body clock drives huge changes in the human body.

It alters alertness, mood, physical strength and even the risk of a heart attack in a daily rhythm.

It stems from our evolutionary past when we were active in the day and resting at night.

But scientists have warned that modern life and 24-hour society mean many people are now "living against" their body clocks with damaging consequences for health and wellbeing.

Prof Russell Foster, at the University of Oxford, said people were getting between one and two hours less sleep a night than 60 years ago.

He said: "We are the supremely arrogant species; we feel we can abandon four billion years of evolution and ignore the fact that we have evolved under a light-dark cycle.

"What we do as a species, perhaps uniquely, is override the clock. And long-term acting against the clock can lead to serious health problems."

He says this is an issue affecting the whole of society, not just shift workers.

Prof Foster said that this was an acute problem in teenagers and he had met children who sleep by popping their parent's sleeping tablets in the evening and then downing three Red Bulls in the morning.

Blue light

Emerging evidence suggests modern technology is now keeping us up later into the night and cutting sleep.

"Light is the most powerful synchroniser of your internal biological clock," Prof Charles Czeisler, from Harvard University, told the BBC Day of the Body Clock.

He said energy efficient light bulbs as well as smartphones, tablets and computers had high levels of light in the blue end of the spectrum which is "right in the sweet spot" for disrupting the body clock.

"Light exposure, especially short wavelength blue-ish light in the evening, will reset our circadian rhythms to a later hour, postponing the release of the sleep-promoting hormone melatonin and making it more difficult for us to get up in the morning.

"It's a big concern that we're being exposed to much more light, sleeping less and, as a consequence, may suffer from many chronic diseases."

Pioneering genetic research is now uncovering how living life against the clock is damaging our health.

About 10% of human DNA has a 24-hour pattern of activity, which is behind all the behavioural and physiological changes in the body.

But studies have shown rhythm can be disrupted by short sleep durations or shift work.

Dr Simon Archer, who conducted the studies at the University of Surrey, said there was a "large impact" on how the body ran.

"These are all fundamental biological pathways that can be underlying links to some of the negative health outcomes that we see such as cardiovascular disease, diabetes, obesity and potentially cancer in people who don't get enough sleep or do shift work," he said.

Experiments show people can become pre-diabetic after a few weeks of shift work.

Dr Akhilesh Reddy, from the University of Cambridge, said the body clock influences every biological process in the human body and the health consequences of living against the clock were "pretty clear cut", particularly in breast cancer.

He said: "Try to live more rhythmically, in tune with the environment and not have too much bright light before bedtime because it will affect the clock and sleep."

Prof Andrew Loudon, from the University of Manchester, said: "The problems caused by living against the body clock may be less sexy than the countless 'this or that causes cancer stories' it is none-the-less a major problem for society."

"You might not notice any short-term changes in your health following circadian disruption, but over a long period of time, the consequences could be quite severe.

"Governments need to take this seriously, starting perhaps with reviewing the health consequences of shift work, and society and legislators needs to take this on board."

Tips for living with your body clock

Ask yourself are you getting enough sleep?

If you need an alarm clock to wake up or are reliant on caffeinated drinks in the morning you need more sleep.

Other signs include being irritable and impulsive, do you take risks while driving?

Prof Russell Foster says people need to "look at lives and take a bit of control".

Your last tea or coffee should not be beyond 1400 as the caffeine lingers in the body.

Minimise light before bed and get a small light for the bathroom for brushing your teeth.

Also stop doing things that grab your attention eg social media and gaming.

Shift workers should have regular health checkups due to the risk of health problems.

The following users thank manthing for this useful post:
SavageAmusement (05-17-2014)

I can't thank you enough for posting this. this is so amazing....ive already shared it with 4 close friends- the whole circadian rhythm thing has been a thorn in my side forever because of a rolling work schedule, this is really a great read.

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"I'm normally not a praying man, but if you're up there, please save me Superman."Homer